THE PERFORMANCE | Throughout Orphan Black‘s freshman run, Tatiana Maslany’s work has been as mind-blowing as the show’s concept: A young woman whose life is in shambles witnesses her doppelgänger committing suicide on a train platform, assumes the dead woman’s police-detective identity and discovers she’s one in a series of at least nine human clones (another of whom is attempting to kill off the entire line).

During the course of “Entangled Bank,” Maslany deftly and distinctly brought to life four different characters going through arcs that were respectively hilarious, heartbreaking, romantic and suspenseful: Uptight soccer mom Alison; psychotic zealot Helena; bisexual science geek Cosima; and tough-gal heroine Sarah (who at one point had to pass herself off as dead cop Beth).

In Maslany’s hands, Alison has been the portrait of prim, suburban conformity — with a hilarious undercurrent of barely suppressed rage. In “Entangled Bank,” we finally saw the character come unravelled: Reeling from her decision to seek a divorce, stressed from keeping her clone status a secret, and suspecting that her bestie neighbor Aynesley might be her “observer,” Alison wound up ditching her daughter’s figure-skating practice, sharing a joint with Aynesley’s dolt husband and then hilariously seducing him in his minivan. When Maslany growled, “I bet you could bounce me like a ball,” you could sense a season’s worth of deeply felt tension on the brink of release. And later, as Alison drove home belting out Meredith Brooks’ “Bitch,” there was a mixture of joy at having decided not to “give an eff” and terror at not knowing how her future would look in the morning. (Just for good measure, we followed up with an Alison-Aynesley slugfest in the middle of their picturesque street — complete with a head to the steering wheel and a car door to the torso. Ouch! And LOL, too.)

Equally mesmerizing was Maslany’s turn as the unhinged Ukranian Helena, who discovered that Sarah, the clone she just can’t kill, has a biological daughter named Kira. Watching Helena in her shipyard hideout, sniffing Sarah’s jacket and reading Kira’s letters to “mommy,” you knew the hour was headed for something dark and derangerd — and sure enough, Helena lured Kira out the door and began to abscond with her. But a funny thing happened on the way to Helena’s creepy keeper: Little Kira sensed something broken in her mother’s “twin” and gave her a hug while whispering, “Helena, what happened to you?” The sudden jolt of being treated like a human being — and not as a programmed assassin/angel of death — opened a tidal wave of emotion, leaving Helena no choice but to let Kira run from their alleyway hiding place toward her screaming mother. Alas, as Kira ran directly into the path of a car, we saw Maslany capture Sarah’s abject horror and shock, as well as Helena’s sense of desperation and guilt.

If this episode doesn’t put Maslany on the Emmy shortlist for Outstanding Lead Actress in a Drama Series, then nobody in a genre series is ever going to stand a chance.